1. Field of the Invention
The present invention relates, in general, products and processes resulting from catalytic processing, and, more particularly, from a method and apparatus for enhanced catalytic processing using catalyst compositions in an electric field.
2. Relevant Background
Chemical and materials synthesis and transformation is one of the core industries of world economy. Numerous substances are synthesized using processes that require non-ambient temperatures and/or non-ambient pressures that require capital intensive equipment. Methods that can produce useful chemicals and materials at conditions closer to ambient conditions and use simple equipment are economically, ecologically, and environmentally more desirable.
Chemical species such as volatile organic chemicals (VOCs), heavy metals in waste water and bioactive chemicals are pollutants of serious concern. A need exists for processes and devices that can convert these substances into more benign forms such as carbon dioxide and water vapor. Techniques currently in use include incineration, absorption/desorption, chemical wash and photocatalysis. Incineration is a high energy process and often leads to non-benign secondary emissions such as nitrogen oxides (NOx) and unburned hydrocarbons. Photocatalysis systems are expensive to install and require high maintenance to avoid degrading efficiencies and treatment reliability. Other techniques lead to secondary wastes and leave the ultimate fate of the pollutants unresolved. A technique is needed that can reliably treat chemical pollutants in a cost effective manner.
Numerous industries use catalytic processing techniques either to produce useful materials and compositions or to reduce waste or pollutants. Examples of such industries include those based on electricity generation, turbines, internal combustion engines, environmental and ecological protection, polymer and plastics manufacturing, petrochemical synthesis, specialty chemicals manufacturing, fuel production, batteries, biomedical devices, and pharmaceutical production. These industries are in continuous need of new catalysts and catalytic processes that can impact the costs and performance of the products generated by these industries.
Currently, processes and methods based on homogeneous and heterogeneous catalysis are integral and important to modern industrial, energy, and environmental chemistry. In petroleum and petrochemical industries, catalysis is used in numerous purification, refining, cracking, and/or reaction steps. In the purification of synthetic gaseous and liquid fuels from crude oil, coal, tar sand, and oil shale, catalysis is important. Approximately two thirds of leading the large tonnage chemicals are manufactured with the help of catalysis. Illustrative examples include acetic acid, acetaldehyde, acetone, acryolonitrile, adipic acid, ammonia, aniline, benzene, bisphenol A, butadiene, butanols, butanone, caprolactum, cumene, cyclohexane, cyclohexanone, cyclohexanol, phtalates, dodecylbenzene, ethanol, ethers, ethylbenzene, ethanol, methanol, ethylbenzene, ethylene dichloride, ethylene glycol, ethylene oxide, ethyl chloride, ethyl hexanol, formaldehyde, hydrogen, hydrogen peroxide, hydroxylamine, isoprene, isopropanol, maleic anhydride, methyl amines, methyl chloride, methylene chloride, nitric acid, perchloroethylene, phenol, phthalic anhydride, propylene glycol, propylene oxide, styrene, sulfur, sulfuric acid, acids, alkalis, terephthalic acid, toluene, vinyl acetate, vinyl chloride, and xylenes.
Further, most of the production of organic intermediates used to make plastics, elastomers, fibers, pharmaceuticals, dyes, pesticides, resins, and pigments involve catalytic process steps. Food, drinks, clothing, metals, and materials manufacturing often utilizes catalysts. Removal of atmospheric pollutants from automobile exhausts and industrial waste gases requires catalytic converters. Liquid wastes and stream also are routinely treated with catalysts. These applications need techniques, methods, and devices that can help research, identify, develop, optimize, improve, and practice superior performing catalysts of existing formulations, of evolved formulations, and of novel formulations.
Many new products are impractical to produce due to high manufacturing costs and/or low manufacturing yields of the materials that enable the production of such products. These limitations curtail the wide application of new materials. Novel catalysts can enable the production of products that are currently too expensive to manufacture or impossible to produce for wide ranges of applications that were, until now, cost prohibitive. A need exists for techniques to develop such novel catalysts.
The above and other limitations are solved by a chemical transformation device and method for processing chemical compositions that provides efficient, robust operation yet is implemented with a simplicity of design that enables low cost implementation in a wide variety of applications. These and other limitations are also solved by a method for making a chemical transformation device using cost efficient processes and techniques.
In one aspect, the invention includes processes and products using a method of chemically transforming a substance through the simultaneous use of a catalyst and electrical current. This method comprises selecting an active material which interacts with an applied electromagnetic field to produce a current. A high surface area (preferably greater than 1 square centimeter per gram, more preferably 100 square centimeter per gram, and most preferably 1 square meter per gram) form of the active material is prepared. The active material is formed into a single layer or multilayered structure that is preferably porous. The stream containing substance that needs to be transformed is exposed to the active material structure while charge flow is induced by the applied electromagnetic field. Where appropriate, the product stream is collected after such exposure.
In a related aspect, the invention comprises a method of manufacturing a device comprising an active material preferably with high band gap (preferably greater than 0.5 eV, more preferably 1.5 eV, most preferably 2.5 eV). The active material is preferably provided a high surface area form such as a nanostructured material or a nanocomposite or a high internal porosity material. A porous structure comprising at least one layer, such as a thin film layer, of the active material and electrodes positioned on the at least one layer to enable an electromagnetic field to be applied across the at least one layer. It is preferred that the resistance of the device between the electrodes be between 0.001 milliohm to 100 megaohm per unit ampere of current flowing through the device, more preferably between 0.01 milliohm to 10 megaohm per unit ampere of current flowing through the device, and most preferably 1 milliohm to 1 megaohm per unit ampere of current flowing through the device.
In case the current flow measure is not known or difficult to measure, it is preferred that the corresponding power consumption levels for the device be used to practice this invention. To illustrate, in case of electromagnetic field is externally applied, then it is preferred that the power consumption due to device operation be between 0.001 milliwatt to 100 megawatt. While miniature, thin film, and micromachined devices may utilize power less than these and applications may use power higher than these levels, and such applications are herewith included in the scope of this invention, in all cases, design and/or operation that leads to lower power requirement is favored to minimize the operating costs by the device. Higher resistances may be used when the chemical transformation step so requires. In case, alternating current is used, the overall impedance of the device must be kept low to reduce energy consumption and operating costs. Once again, the yield, the selectivity, the operating costs and the capital costs of the device must be considered in designing, selecting, and operating the device.
Previous studies have used electrochemical and electrolytic techniques for converting certain species into more desirable species. As an illustration, a voltage when applied across a solid electrolyte (for example an ion conducting membrane) have been reported to cause reversible increases in catalytic activity and changes in selectivity of metals supported on the electrolyte. These results have been explained using the non-Faradaic electrochemical modification of catalytic activity (NEMCA) effect. The present invention is distinct from these studies in at least the following ways:
(1) an electromagnetic field (e.g. voltage) is applied to the catalyst itself, as opposed to an electrolyte, using an external circuit and this causes the current to flow in the catalyst;
(2) reversing the polarity of the electrodes to the catalyst does not change the reaction kinetics or selectivity. Alternatively alternating, sinusoidal, or other types of pulsating currents may be used for embodiments taught herein whereas
(3) current is not needed all the times and may just be used to activate the catalyst in desirable ways, and
(4) reaction takes place on the low impedance catalyst which may be supported by a porous and relatively higher impedance substrate, while electrical current passes through the catalyst. In contrast, for NEMCA effect the substrate (electrolyte) is necessarily conducting.
In another aspect, the present invention provides methods to efficiently provide localized thermal or activation energy at the surface of a catalyst. Additionally, the present invention offers a method of reducing or preventing the need for external thermal energy input.
In another aspect the present invention provides processes that produce superior performing and environmentally benign manufacturing of products through the quench of undesired secondary reactions.
In a related aspect the present invention provides process of developing catalysts and products derived using these catalysts.
In another aspect, the present invention provides a process of producing useful products from raw materials through the simultaneous use of a catalytic surface that stationary with respect to the raw material being processed and an induced field inside the catalyst.
In yet another aspect, the present invention provides methods for the preparation of a device for chemically transforming a species through the use of electromagnetic field. Additionally, the present invention describes products prepared using such devices for chemically transforming a species with electromagnetic field. In another aspect, the present invention describes applications of novel fluid and chemical composition transformation technique.
An exemplary process in accordance with the present invention is operated by first pre-treating a feed composition in a way that changes the free energy of the feed composition to a more desirable state. To illustrate, but not limit, the feed composition may be heated or cooled, pressurized or depressurized, mixed, sparged, evaporated partially or fully, filtered, decanted, crushed into finer particle sizes, emulsified, bio-activated, partially or fully combusted, or separated into desired chemistry using any technique.
Optionally, the pre-treated feed is then either combined with similarly pre-treated feed or untreated feed. The component feeds (i.e., pre-treated feed(s) and untreated feed(s) are preferably thoroughly mixed, but may be mixed to any desired degree. The combination ratios between component feed compositions can be varied widely to meet the needs of a particular application. The resultant feed is then passed over a device comprising of an active material.
The device is operated by placing the active material in a direct current or alternating current electrical circuit that leads to flow of charge. The charge flow can be through flow of electrons, flow of ions, or flow of holes. In one embodiment, it is preferred that during operation, the circuit be switched on first such that charges begin to flow in the circuit. Next, feed material is exposed to the active material for duration desired and the products resulting from such exposure are collected. In another embodiment it is preferred that the feed material be in contact with the active material catalyst first, next the flow of charge is initiated by switching on the electrical circuit. In yet another embodiment, the circuit is switched on to induce flow of charge that initiates the desired reaction which is then followed by changing the electromagnetic field that best favors the performance of the catalyst, the yield, the selectivity, the operating costs and the capital costs of the device. In another embodiment, the circuit is operating in a time varying or pulsating or pre-programmed switching on and off of the electrical circuit to induce corresponding flow of charge through the active material.
In one or more embodiments, the device may be cooled or heated using secondary sources, pressurized or evacuated using secondary sources, photonically and optically activated or isolated using secondary sources, laser activated or field influenced using secondary sources, gas, liquid, solid, ion, or energy influenced using secondary sources. The device may be heated or cooled to desired temperature through resistive or convective or radiative heating for illustration, pressurized or evacuated to desired pressure through piezo effects for illustration, photonically and optically activated to desired photonic influence through phosphorescence affects for illustration. The device may assist such functions by design through the use of the electrical current directly, i.e. the current affects the catalyst and also enables such desired state variables. The device may be free standing or fully supported or partially supported. The device may be operated in steady state, unsteady state, pulsed mode, continuous or batch mode, symmetric waveforms, asymmetric waveforms, in motion or in stationary state. The products from the device are then removed from the neighborhood of the device, collected, and distributed.
In some embodiments, the heating or cooling from the device or unit operations described in this invention may be usefully applied. To illustrate, if the device is being cooled, the heat so extracted may be used to heat another process stream or a space such as the passenger cabin of a car or home.
In another embodiment, the catalytic properties of a substance are modified because of the electromagnetic potential applied to the substance. In such cases, the potential may be applied by an external circuit containing the substance, or the potential may be applied due the presence of another substance which induces a potential because of proximity and difference in chemical potential between the substances. To illustrate the later but not limit, if cobalt nanoparticles were to be intimately mixed with gold nanoparticles, the difference in the chemical potential would induce a charge in the nanoparticles. This charge would induce cobalt interfacial atoms of the cobalt nanoparticles to exhibit nickel like catalytic behavior and gold interfacial atoms of the gold nanoparticles to exhibit platinum like catalytic behavior.